An experiment in ad-hoc protection

protect.red

Red [title: "an experiment with adhoc protection"]

;; problem is that once it's assigned to a deep-reactor, protection is lost
;; and we can only protect series, not maps or objects like this (limitation of ownership system) 

;; REQUIRES https://codeberg.org/hiiamboris/red-common
#include %common/tree-hopping.red

guard: object [
	own: func [s [series!]] [modify s 'owned reduce [self s]]
	on-deep-change*: func [o w t a n i p] [
		do make error! rejoin ["Attempt to modify protected value "mold/flat/part w 40]
	]
]
block-walker: make-series-walker [any-block! any-object! map!]
protect: function [data [series!]] [
	guard/own data
	foreach-node data block-walker [
		if series? :node/:key [guard/own :node/:key]
		:node/:key
	]
]

protect s: [1 2 3 [4] #(5 [6])]
try [append s 7]
try [append s/4 7]
try [append s/5/5 7]
?? s
append s 4

s: [1 2 3 [4] #(
    5 [6]
)]
*** User Error: Attempt to modify protected value [1 2 3 [4] #(5 [6])]
*** Where: do
*** Near : do make error! rejoin ["Attempt to modify" ]
*** Stack: